New To The Yfz

[Dustin075]

Hey Guys, I am new to the yfz and have a question that i am hopeing someone can answer for me. Before I got the the bike it had a pipe and a k an n air filter, but the guy i got it from put it back to stock. So the carb is still jetted for that stuff. Can someone tell me what the stock jetting for a 05 yfz is. It has the exhaust mod done to it if that makes a difference. Thanks

[ohsobad_chevy]

Someone correct me if I am wrong but I think it is:
155 main
42 pilot
3rd clip needle

[greenblood01]

I believe thats right osobad. However if you don't already have the jets I would go ahead and put a 45 pilot in to help eliminate low end and throttle stabbing bog.

Also, knock the plug out of the bowl so that you can adjust the mixture screw without disassembling the carb.

[Dustin075]

It has a boyesen power shot and a numbered air too fuel screw. The bike runs rough, and is hard to start, so i am hope the jetting is way off.

[ohsobad_chevy]

Might check the valves and make sure they are in spec.

[squadie]

I believe the stock main for an 05 is a 158.

[Toadz400]

Originally posted by squadie
I believe the stock main for an 05 is a 158.

Correct.

I would take the carb out and make sure it's clean, never know if he ever let it sit for long and the gas gummed up. I would throw in a 160 main, drop the clip down a position from stock (so 2nd clip from the bottom?), keep the 45 pilot in there if that's what's in there, and adjust the fuel screw.

[Dr89]

i hate to be the pessimest but just from little you've said i think its your valves...

if it had been rejetted for just a pipe and filter and is back to stock now it really wouldnt run THAT bad...but it would be rich so check your spark plug--could be the reason for the hard starts